Spray tanning explained

Sunless tanning is chemistry, not radiation. Understanding how it works is most of what you need to get a good result and avoid the classic mistakes.

A spray tan does not tan you. It stains you — and understanding that distinction is the key to everything else on this page, from why exfoliation matters to why the colour fades unevenly if you skip the moisturiser.

How DHA works

The active ingredient in virtually all sunless tanning products is dihydroxyacetone (DHA), a colourless sugar derivative. When applied to skin, it reacts with amino acids in the outermost layer — the stratum corneum, which is made up of dead skin cells — in what chemists call a Maillard reaction. It is, broadly, the same class of reaction that browns toast.

Three consequences follow directly, and they explain almost everything about spray tanning:

• The colour develops gradually, typically over several hours, because the reaction takes time. Full development is usually reached somewhere around eight hours.
• It only affects dead surface cells. It does not penetrate deeper, does not enter the bloodstream in any meaningful way and does not involve pigment production.
• It fades as those cells shed. Your skin renews itself continuously, so the tan wears off over roughly five to ten days — and it fades unevenly wherever your skin sheds faster.

Many products also contain a cosmetic bronzer: a temporary guide colour that lets the technician see where they have sprayed and gives you instant colour. It washes off in the first shower, leaving the developed DHA colour behind. If your tan looks dramatically lighter after the first rinse, that is usually the bronzer going, not the tan failing.

And the point that bears repeating: DHA offers no ultraviolet protection. A spray tan is not a substitute for sunscreen. See the tanning guide.

Preparation: where the result is decided

Most disappointing spray tans are lost before the technician picks up the gun.

• Exfoliate 24 hours beforehand. DHA develops on the surface layer, so an uneven, built-up surface produces an uneven, patchy tan. Use a gentle scrub or exfoliating mitt, paying attention to knees, elbows, ankles, knuckles and feet, where skin is thickest.
• Do the exfoliation the day before, not the same day, so the skin has time to settle.
• Shave or wax at least 24 hours in advance. Freshly shaved skin has open follicles, which take up more colour and produce dark spots. Waxing on the day risks irritation and patchiness.
• Arrive with completely clean, product-free skin. No moisturiser, no deodorant, no perfume, no make-up, no oils. These create a barrier and cause patches — deodorant is a particularly common culprit for green-tinged underarms.
• Wear loose, dark clothing and flip-flops afterwards. Tight waistbands, bra straps and socks will mark a developing tan.
• Patch test if you have sensitive skin or have reacted to cosmetics before. Reactions to sunless tanning products are uncommon but not unheard of.

The application

You will usually be asked to undress to your comfort level; disposable underwear is normally offered. A barrier cream is applied to the driest, most absorbent areas — palms, soles, nails, and often knuckles, elbows, knees and ankles — because those areas grab colour. A protective cap covers the hair and sticky feet protect the soles.

The technician sprays in sections, asking you to move into particular positions. It takes ten to twenty minutes. A good technician will discuss the depth of colour with you first and steer you away from going too dark on a first appointment — the most common regret in this entire treatment.

Aftercare

• Do not get wet until the recommended development time has elapsed — typically anywhere from four to eight hours, and some rapid formulations are shorter. Follow the specific advice you are given.
• Avoid sweating. No gym, no hot yoga, no strenuous exercise until after the first rinse.
• First shower: warm water only, no soap, no scrubbing. Rinse until the water runs clear as the bronzer comes off. Pat dry with a towel — do not rub.
• Moisturise every day, generously, from the first shower onwards. This is the single biggest factor in how long the tan lasts and how evenly it fades. Dry skin sheds faster, and a shed cell takes its colour with it.
• Avoid long hot baths, swimming pools, saunas, hot tubs and chlorine, all of which strip it.
• Avoid exfoliating scrubs and, in particular, oil-based products for the life of the tan; oils break down the colour.
• Pat, do not rub, when drying.

Streaks, orange tones and how to avoid them

Orange is almost always a mismatch between the depth of the formulation and your natural skin tone — too dark for the base you have. It is not a sign that the product has "gone wrong". Go one shade lighter than you think you want, and build up over repeat appointments.

• Streaks usually mean uneven preparation, product on the skin at application, or the tan being disturbed before it developed. Sleeping in tight clothing or sitting in a car with a hot back are common causes.
• Dark patches on knees, elbows, ankles and knuckles mean insufficient exfoliation or barrier cream on the dry areas.
• Dark spots on the legs often mean shaving too close to the appointment.
• Patchy fading almost always means insufficient moisturising.
• Staining of the palms means barrier cream was skipped, or you touched the tan while developing. Wash your hands immediately if you do.
• To remove a tan you dislike, exfoliate persistently, take long warm baths and use an oil-based product — the same things you avoid when you want it to last.

Read next: skincare basics, treatments explained and choosing a salon. Back to the homepage.

Independent guide. Not a salon; no treatments, no bookings.