The difference is pulse length. A nanosecond is a billionth of a second and a picosecond is a trillionth — but "picosecond" here is a category name, not a specification. Real cleared devices fire pulses of roughly 240 to 900 picoseconds, against about 5 to 20 nanoseconds for a Q-switched laser. So the practical gap is around ten to forty times shorter, not a thousand.
A shorter pulse changes how the target breaks. Older nanosecond lasers work mainly by heating pigment until it fractures. A picosecond pulse is short enough to add a mechanical shock, shattering the particle rather than only cooking it. With a lens attached, it can also create tiny cavities in the skin that trigger a repair response.
Where that pays off is narrower than the marketing suggests. It is real for some tattoo colours and for acne scarring. It is not established for general brown pigment.
PicoWay is the shortest at 240 to 500; PicoSure runs 450 to 900.
Short enough to shatter pigment rather than only heat it.
Pigment absorbs the energy, heats rapidly and fractures.
A systematic review reached that conclusion. A randomised trial found about a third of pico-treated tattoos reaching 75% clearance against about one in seven with the older laser.
A head-to-head against a common fractional laser favoured picosecond.
The 755 nm setting usually settles within a day. The 532 and 1064 nm settings often leave pinpoint bruising visible at 24 hours.
Picosecond lasers were launched on the promise of fewer sessions and better clearance. Here is where that survives contact with the evidence.
It holds for coloured tattoo ink. A systematic review concluded that picosecond lasers clear blue, green and yellow better than older ones. The evidence is not uniform, though — the best single randomised trial found an overall picosecond advantage but no specific benefit on multicoloured tattoos.
It holds for acne scarring. In a head-to-head trial against a common fractional laser, picosecond scored better.
It does not hold for black ink. The two performed about the same.
It does not hold for general brown pigment, where no clear superiority has been demonstrated.
And it does not hold for melasma, where a meta-analysis found no significant benefit.
None of this makes picosecond lasers bad — they are excellent machines. It means the premium is worth paying for some jobs and not others, and a clinic should be able to tell you which yours is.
Pico Genesis is a treatment protocol, not a device. It runs on the enlighten laser. If you are quoted "Pico Genesis," you are being quoted a technique — fine in itself, but you cannot line that name up against a device name as if they were the same kind of thing.
Also worth knowing: at least one device in this class offers both a picosecond and a nanosecond mode, and the operator chooses. So "I had a pico laser" does not always mean every pulse was picosecond.
If you get cold sores, tell your provider. Laser treatment can reactivate the virus, and antiviral medication started in advance is the standard precaution.