Best D3 alternatives: apps like D3-Sync: Sun & Supplements

SolGlow: Vitamin D Tracker

Automatic Sunlight & UV Index

Free

This app automatically estimates your daily vitamin D intake based on sunlight exposure, skin type, and location. It provides real-time UV index, burn-safe time remaining, and integrates with Apple Watch for effortless tracking. Features include winter mode, supplement check-ins, and advanced planning tools for Pro users.

Sunshine — Vitamin D Tracker

Sunscreen Timer, SPF & UV

Free

Effortlessly track your daily natural light exposure to optimize vitamin D production and improve sleep. Get personalized safe sun timers and daily goals to build healthy outdoor habits.

Vitamin D Window Widget

Vitamin D Availability Window

Free

This app displays the optimal times of day for natural vitamin D production based on your location and the sun's elevation. It offers real-time sun schedules, smart widgets for home screen access, and notifications to help you maximize your sun exposure.

Vitamin D Sun Tracker & UV

UV Index, Sunburn & SPF Timer

Free

This app personalizes your sun exposure to optimize vitamin D production and prevent sunburn. It uses your location, skin type, and real-time atmospheric data to determine the best times to be in the sun and when to cover up. Integrates with Apple Health and Apple Watch for seamless tracking.

Navy Body Fat Calculator Pro

Master Your Body Composition

$0.99

This app helps you accurately calculate your body fat percentage using the U.S. Navy's trusted method. Simply input your measurements and get instant, reliable results for a better understanding of your body composition.