A 25W LED should be plenty. That is roughly the same as a 100W incandescent bult. Just get it down within an inch or two of the pepper seedlings. How warm is it where the pepper plant is growing?

Here are some Reaper plants about three weeks after the day I planted them.

Could you provide a pic of the plant and light? We can better give advice with a pic.

I use a 300 watt led which is actually 140 watts or so. It uses 5 watt chips but runs around 3 watts. This gives long life and it has virtually no heat. Cost $70 on ebay. This reaper was grown from seed under it. The new seedings are a few days old. They are ghosts. You want leds around 12-18" from the plants. Too close and you wont get the full spectrum. Here is the pics. The other is a Brazilian ornamental grown from seed. There are 2 plants in the small pot.