In hand luggage, liquid shampoo is restricted to 3.4 oz (100 ml) bottles or smaller. If you’re carrying a larger shampoo bottle, it won’t be allowed, even half-full. All liquids in hand luggage also must be packed in a clear, resealable, 1-quart-sized bag.

Liquid shampoo is restricted to such small quantities because it’s considered a security threat by the TSA. Their scanners can’t distinguish between safe and unsafe, potentially flammable liquids.

The only exception is medically necessary shampoo. If you have a prescription for it, then TSA allows bringing larger quantities of it in your hand baggage. But you should only bring the amount required for your trip and not much more. In this case, you can explain to the TSA officer your condition and show them the prescription.

In checked bags, these restrictions don’t apply – liquid shampoo is allowed in any size or quantity.

Rules for Traveling With Other Types of Shampoo

Dry Shampoo

Dry shampoo has almost identical rules to liquid shampoo because all aerosols contain liquid. But because it’s flammable, it has additional quantity restrictions for checked baggage.

In checked bags, each passenger can bring dry shampoo up to 500 ml (17 fl oz) in size. And in total, each passenger can have up to 2 liters (68 fl oz) of aerosols in their baggage.

Powder Shampoo

Powder shampoo is allowed in hand and checked baggage in any quantity or size. But if it’s above 350 g (12 oz) and it’s packed in hand luggage, it has to be placed in a separate bin for screening. If possible, you should pack powder shampoo above 350 g (12 oz) in checked baggage, especially when flying internationally.

Shampoo Bars

Shampoo bars are treated as a solid, so they have no quantity or size restrictions in hand or checked baggage.

Traveling With Shampoo Internationally

Generally, the rules for packing liquid shampoo in luggage are identical across the world. There are exceptions for domestic flights in  Australia and New Zealand and flights departing from a few airports in the UK and the US.

On these flights, liquid shampoo isn’t restricted to small quantities in hand baggage. That’s because the airports are fitted with modern scanners, which can scan liquids in larger quantities.

Another thing to remember is that large powder shampoo containers over 350 g (12 oz) are banned from hand luggage in some countries. So when traveling internationally, larger power shampoo containers should only be stored in checked bags.

How to Pack Shampoo in Luggage

Shampoo bottles shouldn’t explore or burst open from pressure changes when packed in checked baggage. That’s because all modern cargo compartments on planes are pressurized. The only thing that can cause spills is damage during baggage handling.

To avoid spills, put a piece of duct tape over the lid of the shampoo bottle, essentially sealing it in place. Also, don’t place the bottle near the edges of the suitcase and wrap it in soft clothing. This will keep the bottle from accidentally being squeezed during baggage handling.

A 100 ml (3.4 oz) shampoo bottle won’t last very long, especially if used by many people. So realistically, you should pack a larger shampoo bottle in your checked bag or buy it at your destination. For shorter 1-week vacations, 100 ml bottles are more than enough, so you can bring a smaller bottle and pack it in your carry-on.

Rules for Other Hair Care Products

• Hairspray is treated identically to dry shampoo. It’s limited to 3.4 oz (100 ml) bottles in hand luggage and 500 ml (17 fl oz) bottles in checked bags.
• Conditioner, hair gel, and other hair pastes, clays, or lotions are all treated as liquids. If you can smear it, it’s considered a liquid, so it’s limited to small bottles in hand baggage. In checked bags, larger quantities are allowed.

Summing Up – Traveling With Shampoo

Traveling with liquid shampoo and conditioner is a bit awkward because it takes up a lot of space and you need a lot of it if you wash every day. I’ve found that a much better alternative is to use a shampoo bar or travel soap. That’s because they don’t take up a lot of space, they don’t have any packing restrictions, and they last much longer.