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User Guide

How Protein Targets Are Calculated

MuscleAI doesn't use a generic protein formula. Your daily target is built specifically around your body, your activity level, your age, and — if applicable — your GLP-1 medication. Here's exactly how it works.

Step 1: Lean Body Mass (Boer Formula)

The starting point is your lean body mass (LBM) — the weight of everything in your body that isn't fat. Muscle needs protein to maintain; fat doesn't. So protein targets are based on LBM, not total body weight.

We use the Boer formula, a well-established method in clinical nutrition:

For men:

LBM (kg) = (0.407 × weight in kg) + (0.267 × height in cm) − 19.2

For women:

LBM (kg) = (0.252 × weight in kg) + (0.473 × height in cm) − 48.3

Step 2: Base Protein Rate

Your LBM is multiplied by a base rate depending on your selected mode (Standard, GLP-1, Bulk, Cut, Plant-Based, etc.). This rate reflects how much protein per kg of lean mass is needed to preserve or build muscle for that goal.

Step 3: Activity Level Adjustment

Your activity level (Sedentary, Lightly Active, Moderately Active, Very Active) adjusts the base rate up or down. More activity means more protein turnover and a higher target. Sedentary users get a slightly reduced multiplier; very active users get the full or increased rate.

Step 4: Age Adjustment

Research shows older adults need more protein per meal to achieve the same muscle protein synthesis response as younger adults (Moore et al.). MuscleAI applies:

Age Range Adjustment
Under 36 No adjustment
36–50 +5%
51–65 +10%
65+ +15%

Step 5: GLP-1 Medication Adjustment (GLP-1 Mode Only)

Different GLP-1 medications suppress appetite to different degrees. The stronger the appetite suppression, the more important it is to be deliberate about protein. MuscleAI applies a medication-specific multiplier: