In short. Hair colour, skin type and how the skin behaved after previous treatment decide what can safely be used, and the assessment comes before the course.
Key points
- Whether either option is suitable, which one is proposed, and how the course is planned.
- A course started without that assessment is a course planned from a request rather than from the hair and skin in front of the clinician.
Both of these options are chosen at an assessment rather than at a reception desk. The assessment establishes what the hair is like, what the skin is like, and what has been tried before, and those findings decide whether a course is suitable at all, which instrument is proposed, and how the sessions are spaced.
The hair
The colour and the coarseness of the hair are examined, because both options depend on pigment in the hair carrying the light into the follicle. Dark, coarse hair responds best. Light, grey, red and white hair contains little of the pigment the treatment needs, and that is true whichever instrument is used. The area is examined too, because hair in one area does not behave like hair in another, and the density and the growth pattern both affect what a course can achieve.
The skin
The skin type is established by asking how it tans and how it burns, and by examining the area being treated. That matters twice over: the contrast between the skin and the hair is what makes the treatment work, and the pigment in the skin is what absorbs energy that was meant for the hair. On darker skin the margin between a setting that works and one that damages is narrower, and the settings are chosen accordingly.
What the assessment is really deciding
Whether either option is suitable, which one is proposed, and how the course is planned. A course started without that assessment is a course planned from a request rather than from the hair and skin in front of the clinician.
The history and the medicines
Previous light treatment and how the skin responded to it are part of the assessment, because a skin that reacted badly once is likely to react badly again. The medicines being taken matter as well, because some make the skin sensitive to light, and the assessment is where that is discussed. So does any skin condition in the area, because some are made worse by treatment and need to be settled first.
What the assessment should produce
A statement of what was found about the hair and the skin, an explanation of which instrument is proposed and why, the expected number of sessions and how they will be spaced, what the skin is expected to do after a session, and what would be treated rather than left. It should also include the honest version: where the hair is unlikely to respond, that belongs in the same conversation.
What postpones a session
- A fresh tan, sunbed use or recent sun exposure in the treated area, which changes how the skin absorbs the light.
- An active skin infection, broken skin or an untreated skin condition in the area.
- A change in the medicines you take, which is worth mentioning before the next session rather than after it.
The assessment is not a formality before a course. It is where the decisions that make the course safe and realistic are made, and it is the same for both instruments.
Frequently asked questions
Why does the assessment look at my skin type rather than only my hair?
Because the treatment depends on contrast between the two, and because the risk of a burn or a pigment change depends on how much pigment there is in the skin. A setting chosen for the hair alone, without reference to the skin it has to pass through, is how burns happen. Skin type is also what decides the starting settings for the course.
Do I need to stop any medicines before treatment?
Some medicines make the skin sensitive to light, and that is a conversation for the assessment rather than something to decide alone. Do not stop a prescribed medicine because of a planned light treatment without speaking to the clinician who prescribed it. What matters is that the treating team knows what you take.
Should I avoid the sun before a session?
Yes. A fresh tan or recent sun exposure in the treated area is a reason to postpone a session, because the extra pigment in the skin changes how the light is absorbed and raises the risk of a burn or a pigment change. That applies to both options and to sunbeds as well as to sunlight.
Risks & Limitations
- No result can be guaranteed, and hair reduction is not the same as permanent hair removal.
- Burns, blistering and pigment change are possible with both options, and are more likely when the settings do not match the skin or the skin has been tanned recently.
- Hair returns over the months after a course, and both options need maintenance rather than one course.
- Neither option works well on light, grey, red or white hair, because both depend on pigment in the hair.
When to Seek Care
- A blister, or skin that is weeping or breaking down in the treated area.
- Pain that is increasing rather than settling, or redness that is spreading.
- A change in skin colour — lighter or darker — that is spreading rather than fading.
- Any reaction in the treated area that is worsening rather than settling in the days after a session.
References & Further Reading
- American Academy of Dermatology (AAD) — hair removal and laser safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.