How to judge a therapy
Hormesis, the evidence ladder, and what 'FDA cleared' actually means.
Stressors, signals and claims
The products on the Therapies shelf work — or claim to work — in three different ways, and knowing which one you're buying tells you what evidence to look for:
- Stressors: heat and cold. A short, controlled dose of discomfort that your body adapts to.
- Signals: bright light, which tells your body clock what time it is through your eyes.
- Direct tissue claims: red / near-infrared light and PEMF, said to act on the cells they reach.
Hormesis: the dose makes the difference
A small dose of stress followed by recovery triggers repair and adaptation — better heat tolerance, more responsive blood vessels, a calmer reaction to cold. Too much, too often, or with no recovery tips adaptation into harm. Every therapy on this shelf has a dose, and 'more' is rarely 'better'.
Cell and animal studies show how something could work. Many product pages stop here ('activates mitochondria', 'boosts heat shock proteins'). Necessary, never sufficient.
Why you can't fake a sauna — but you can fake a light panel
The fairest test compares a therapy against a fake version that looks and feels real. Some therapies can be faked convincingly; some can't. That changes how much you should trust the studies.
Cleared, approved, registered, 'wellness'
- FDA approved (premarket approval): the strictest device pathway. The maker must show reasonable assurance of safety and effectiveness, usually with clinical data. Rare on this shelf.
- FDA cleared (510(k)): the device was shown to be 'substantially equivalent' to one already on the market, for a specific stated use. New clinical trials often aren't required, and the clearance covers only that use.
- FDA registered / listed: the company filed paperwork about its facility or product. Nobody reviewed whether it works.
- General wellness product: low-risk items making broad claims like 'supports relaxation'. The FDA generally doesn't review these at all.
Check a 'cleared' claim yourself: ask for the 510(k) number and look it up in the FDA's public database. The 'Indications for Use' tell you exactly what was cleared — for many infrared and red-light lamps that's topical heating for temporary relief of minor muscle and joint pain, not skin, hormones or longevity. Outside the US, a CE mark on a wellness product mainly speaks to product safety, not to whether the therapy works.
A red-light panel is advertised as 'FDA cleared'. What does that most reliably tell you?