Last updated: April 2026 (revision 4)
Rejuvify is the health app; OptiChroniX is the company that provides it.

This guide explains how to use Rejuvify: connecting devices, reading your scores, logging nutrition, using the meal planner, and getting the most from Premium features.

Important notice

Rejuvify provides lifestyle and wellness information only. It is not a medical device and does not provide clinical medical services. Always talk to a qualified healthcare professional about medications, symptoms, and how to interpret clinical measurements such as blood pressure. If you have a medical emergency, call your local emergency number.

1. What Rejuvify does

Rejuvify helps adults—especially those focused on healthy aging and metabolic resilience—combine:

• Vitality Index — in the app menu; the Vitality screen title is Lifestyle Vitality Index. It is a real-time score from the latest synced data whenever you open Vitality or tap Refresh, reflecting activity, sleep, recovery, and body composition from your connected devices (not a fixed “once per day” snapshot if your data has updated).
• Nutrition tracking — log meals, see protein and macronutrients, and align with your goals (Nutrition Tracker in the menu).
• Meal planning — generate structured weekly plans and save them for reference (Meal Planner / Generate).
• Muscle Protection Index (Premium) — labeled Muscle Protection Index in the main navigation. It is the dashboard for muscle-support habits during weight-change phases (protection score, weight-change pace, protein, strength training, and related signals). When you indicate GLP-1–related therapy in your health profile and the safeguard applies, it also ties into Vitality as a card and optional headline adjustment (§7). Quick settings on this screen let you turn tracking on for reduced appetite or weight change and adjust protein/strength preferences. Optional Muscle Protection Index Program (weekly curriculum) is in §9. Settings also offers Muscle Preservation Mode for nutrition emphasis.
• AI Health Coach (Premium) — conversational guidance grounded in your synced data and recent meal logs.

The sections below walk through each area step by step.

Connected devices — strongly recommended: For the best experience, connect at least one primary health source (Garmin and/or Withings) and keep sync enabled. Vitality, the Muscle Protection Index dashboard, and the Health Coach are most accurate and useful when Rejuvify can use up-to-date data from your wearables and smart scale—not manual estimates alone.

2. Account, sign-in, and Premium

Sign in

Use Sign In from the header or home page. You can sign in with email and password, or with Apple or Google where those buttons appear. If you use email and forget your password, use the password reset flow linked from the login page.

Premium vs free

Premium typically includes:

• Full Lifestyle Vitality Index dashboard and history.
• Muscle Protection Index dashboard and related insights.
• AI Health Coach chat.
• Meal plan generator (unlimited personalized weekly plans, grocery lists, PDF-style export where available in the app).
• Muscle Protection Index Program hub—optional weekly curriculum and check-ins (where enabled in your build).

If you are not Premium, some screens show an upgrade message. Signed-in free members who open Vitality see Vitality Lite: a limited preview (for example today’s headline score and pillar coverage hints) rather than the full Lifestyle Vitality Index dashboard, history, and pillar tools—Upgrade takes you to Pricing. Nutrition tracking is available when you are signed in (it is not behind the same Premium gate as the full Vitality experience). Exact entitlements may evolve; check Pricing and your Settings → Subscription area for your account.

Subscription and billing

Open Settings, then use Manage billing / subscription controls to open the Stripe customer portal (when your plan uses Stripe). There you can update payment methods and view renewal dates.

3. Language (English / Deutsch)

In Settings, choose Language to switch the interface between English and German. Open Help (user manual) from More → Help; the on-page manual and Download PDF follow your current language when a translated file is available, otherwise English is used.

4. Home dashboard

After sign-in, Home shows a greeting, your Vitality summary (when available), quick actions aligned with the app grid (Nutrition logging, Lifestyle Vitality Index, Muscle Protection Index, Meal Planner), links to Ask AI Coach on the Vitality and Muscle Protection cards when shown, and Settings from your account menu. Health Data in the header opens your Profile device integrations. Use Refresh where offered to reload scores after syncing devices.

5. Health Data (Profile) — devices

Open Health Data from the header (when signed in); it goes to Profile where you manage device integrations. Connecting devices is central to Rejuvify—without them, scores and coach answers rely on limited or manual input.

Garmin

Connect Garmin to sync steps, activity, sleep, heart rate, stress, Body Battery, and related metrics used in your Vitality score. Rejuvify receives Garmin wellness data via server push (not a continuous live pull), so updates arrive after your device syncs with Garmin and Garmin forwards summaries. Follow the in-app authorization steps. If data looks stale, reconnect or wait for the next sync cycle, then open Vitality and use Refresh.

Withings

Connect Withings for weight, body composition, blood pressure, and compatible sleep or activity data. This feeds the Body pillar and related insights.

WHOOP

Connect WHOOP under Health Data if you use it. When Garmin (or another daily step/calorie source) is not available, Rejuvify can use WHOOP workouts, strain, and related signals to help drive the Activity pillar and labels—step counts may not be provided by this integration, so activity copy may describe workouts and strain instead of steps.

Tip: Vitality and the Muscle Protection Index dashboard work best when at least one primary source (Garmin and/or Withings) is connected and syncing regularly. WHOOP can complement or substitute for daily Garmin-style metrics depending on what is connected.

6. Settings

Settings is organized into sections (labels may vary slightly by locale):

Support: For account or billing help, contact info@optichronix.com (or the address shown in Settings if we display it there).

7. Vitality Index (Premium)

The Vitality page uses the full title Lifestyle Vitality Index in the header; the main menu uses Vitality Index. Vitality shows:

• Overall score (0–100) and tier (e.g. Optimal, Moderate, Low)—computed from the newest available device and profile data when you load or refresh the screen.
• Four pillars: Activity, Sleep, Recovery, Body composition—each with sub-metrics when data exists.
• History charts for recent trends.
• Data completeness so you know how much of the score is based on real measurements vs. gaps.

Activity (Garmin-first when connected): When Garmin is connected, the Activity pillar is driven primarily by Garmin daily summaries. It combines steps, active calories, active time (active minutes), and intensity minutes (moderate plus vigorous minutes from Garmin). On bike-, swim-, or strength-heavy days—where steps stay low but calories and training load are high—the model may apply movement-forward weighting (more emphasis on calories, training time, and intensity than on steps). A short explanation can appear under the Activity pillar when that applies. Rejuvify does not inflate step counts with synthetic “estimated steps” from other signals.

Recovery: Uses metrics such as resting heart rate, optional blood pressure, stress, Body Battery, and HRV when Garmin (or another source) supplies them. Garmin may send multiple partial uploads per day; Rejuvify merges Body Battery values across those uploads for the same calendar day so the Recovery detail can show a battery value even when one “best” summary row did not include it. HRV may appear as unavailable in Vitality if your current Garmin feed does not include HRV in the wellness snapshot the app uses—your Garmin device or another app screen may still show HRV trends separately.

Pillar details and “N/A”: Detail rows (e.g. active minutes, intensity minutes, Body Battery, HRV) show N/A when that field was not present in the latest data used for that request—for example before the next sync writes active time or intensity for the day, or when HRV is not in the snapshot. Use Refresh after syncing your watch; ensure Health Data shows Garmin connected.

Local day and updates: Vitality uses your local calendar day (timezone from your browser/device when you load the page) so “today” matches where you are. Scores refresh when you open the screen or tap Refresh; they are not a fixed once-per-day snapshot if newer sync data arrives.

Intraday / day progress: Where available, you can open a day progress or timeline view to see how the headline score evolved during the current day—useful after new syncs.

Muscle Protection Index (GLP-1 therapy): If you indicate GLP-1–related therapy in your health profile (and the safeguard logic applies), Vitality may show a Muscle Protection Index card and a headline adjustment that reflects muscle-support behaviors (protein, strength activity, pace) alongside the four-pillar composite. On-screen text explains how the headline score relates to the pillar subscores and the index. Open the full Muscle Protection Index dashboard from the grid menu (Muscle Protection Index), Home quick actions, or the Vitality area when linked. This is wellness support, not a medical device output.

Open pillar sections to see details (steps, sleep stages, HRV, weight, muscle mass, blood pressure, etc.). Use Ask AI Coach (Premium) from relevant screens to discuss your numbers in plain language.

Muscle Protection Index tracking (when enabled on the Muscle Protection Index screen) may also adjust the headline; the UI explains the logic when present—read the on-screen notes.

8. Muscle Protection Index (Premium)

Open Muscle Protection Index from the grid menu or Home quick actions. The app does not use a separate top-level label “Weight-Loss Mode” in navigation; habit support during weight change is centered on the Muscle Protection Index screen.

You will see:

• A protection score (0–100) and component signals—for example weight-change pace, protein adequacy, strength training, and lean-mass–related inputs—explained in the app.
• Quick settings on the same screen for Muscle Protection Index tracking (Experiencing reduced appetite or weight change), protein logging mode, and strength-activity tracking, plus links to profile settings when needed.

Settings → Advanced may show Muscle Preservation Mode for broader nutrition emphasis; that complements the Muscle Protection Index dashboard. If you have medical guidance from a qualified healthcare professional, follow that guidance.

9. Muscle Protection Index Program (curriculum) (Premium)

If your account includes the structured Muscle Protection Index Program, you can enroll, work through weekly program modules and check-ins, and track progress in the program hub. The app uses this same name—do not confuse it with the Muscle Protection Index dashboard (§8), which is the day-to-day scoring surface; the program adds paced curriculum and check-ins alongside the index and Vitality (§7). Some weeks may unlock over time based on completion and scheduling rules shown in the app—this is intentional pacing, not a bug.

10. Nutrition Tracker

The Nutrition Tracker is your today view: protein toward your daily target, calories, and carbs and fat in the Today’s Nutrition summary. Use Refresh to reload after logging. The calendar icon opens History so you can browse other days.

Frequent foods

The Frequent foods section lists items you log often. Star favorites and tap an item to log it again quickly—the app uses your last portion when it can. You can remove entries you no longer need.

Ways to log

Use Log a meal on the hub:

• Take Photo — AI-assisted detection from a new photo or upload from gallery. When offered, choose List foods (multiple ingredients, default) or One dish (one name for the whole meal). The browser controls camera permission; after you allow access for this site, it usually persists until you use Private Browsing, clear site data, or change Safari website settings. Review detected foods, adjust portions, then save. On the review screen you can Save as meal template to reuse the same combination later.
• Scan Barcode — camera scan or manual barcode entry. Nutrition data comes from Open Food Facts and may include community-submitted products—treat community rows as unverified and adjust portions if something looks off. If a code is missing, you may add a community entry (values per 100 g) so the product can be found next time. You can report questionable community data when the app offers it.
• Add Manually — opens Search with two main flows: Search (USDA and Open Food Facts, with locale-aware results where supported) including portion controls and recent searches on your device; and Quick add for custom foods you define (calories, protein, carbs, fat, and portion size) for fast repeat logging. After you assemble items, you can Save as template for one-step logging later.
• Templates — open saved meal templates and log one as today’s meal in a single step, or delete templates you no longer need. New templates are created from photo review or Add manually via Save as template.

History

In History, pick any past day to see that day’s meals (you cannot navigate into the future). Use Log again on a past meal to duplicate it into today with the same foods and portions, then adjust from Nutrition if needed.

Meal detail

Open a meal from today’s list or History to see line items, totals, notes, and how the meal was logged (photo, barcode, or manual). Delete a meal from its detail screen when needed.

Targets

Daily protein shown on the hub comes from your Settings (for example Advanced protein level and related profile fields) and the app’s nutrition target logic. Optional calorie and macro targets apply when configured for your account. The coach and Muscle Protection Index context may use your recent logs (typically about the last seven days) when giving feedback.

11. Meal planner and generator

Saved meal plans

Meal Plans lists plans you have already generated or saved. Open a plan to view the full week, macronutrients, and export options where available.

Generator (Premium)

Meal Planner / Generate walks you through preferences (diet style, fasting window, calories, protein, restrictions). Submit the form to create a new 7-day plan, grocery list, and prep guidance. Premium is required for full generator access.

12. AI Health Coach (Premium)

Health Coach is a chat that uses:

• Your latest Vitality and device-backed metrics.
• Muscle Protection Index context when relevant.
• Logged meals from roughly the last seven days (including food line items when you logged them).

Ask specific questions (“How was my protein logging today?”, “What should I prioritize this week?”). The coach is not a substitute for medical care; it will avoid medical determinations or giving medication-change instructions.

If the manual states there are no meal logs in the window, the coach will say so—log meals in Nutrition to get food-specific answers.

13. Progress Hub and gamification

Progress Hub and Leaderboard show engagement features such as XP, streaks, and league-style comparisons. Use them for motivation; they do not replace clinical metrics.

14. Guides and other pages

Open More in the header to reach Help, Longevity Nutrition Guide, Healthy Aging Guide, Metabolic Resilience Index, and Principles. Visitors and signed-out users also see How It Works and Pricing from the same menu or the marketing home page.

15. Notifications

If enabled, the app may show notifications or an inbox bell for reminders and updates. Adjust preferences in Settings or notification controls where provided.

16. Privacy and data

Health and nutrition data are tied to your account and used to compute scores and recommendations inside the product. Review the published privacy policy on the OptiChroniX marketing site for details on processing, retention, and your rights.

17. Troubleshooting

18. Admin

Some organizations have an Admin panel for internal tools. It is not part of the standard member manual—if you see it, use it only as authorized by your administrator.

Thank you for using Rejuvify. For product feedback or help, email info@optichronix.com or use the contact information in Settings.